Clinical Research Directory

Inclusion Criteria: 1. 18-75 years old. 2. HR+/HER2- breast cancer (BC), meeting the following conditions: 1. HR+/HER2-; HER2-(IHC 0 or 1+); IHC 2+(FISH negative); HR+ (ER and/or PR IHC showed ≥1%); 2. Tumor stage: Locally advanced, recurrent, or metastatic HR+/HER2- breast cancer; 3) Disease progression during or within 12 months after completion of adjuvant endocrine therapy based on a CDK4/6 inhibitor, or disease progression on CDK4/6 inhibitor treatment for metastatic disease; 4) PD-L1 positive (CPS ≥ 1); 5) At least one measurable target lesion as assessed by the investigator per RECIST 1.1; subjects with bone lesions only Exclusion Criteria: 1. Received chemotherapy during the advanced stage; 2. Received any targeted therapy against topoisomerase I during the advanced stage, including antibody-drug conjugates (ADCs) (e.g., anti-CTLA-4 antibodies), immune checkpoint agonists (e.g., ICOS, CD40, CD137, GITR, OX40 antibodies), or any immune cell therapy targeting 3. Received immune checkpoint inhibitors (e.g., anti-PD-1/L1 antibodies) in the advanced stage; 4. Recurrence or metastasis within 12 months of the last chemotherapy in the early stage; 5. Subjects with central nervous system (CNS) metastases. For subjects with brain metastases who have previously received local therapy, 6. Other malignancies within 5 years prior to dosing (excluding locally treated and cured tumors such as basal cell carcinoma, squamous cell carcinoma of the skin, or cervical carcinoma in situ);